Metallizing chamber viewing system

ABSTRACT

A mirror is placed within a metallizing chamber having a transparent viewing port in a position so as to shield the viewing port from the metal source. The mirror is also positioned to reflect a view of the object being metallized through the viewing port. If required, a second mirror may be used to reflect a view of the object to the first mirror.

D United States Patent 11113,620,604

[72] Inventor ghltlimllsufl- B nham [561 References Cited UNITED STATESPATENTS [21] L004 2 401 443 6/1946 w 11 118/49 22 Filed 1111.6,1970 1[45] Patented Nov. 16, 1971 Primary Examiner-David Schonberg [73]Assignee The United States of America as Assistant ExaminerMichael J.Tokar represented by the United States Atomic Attorney-Roland A AndersonEnergy Commission [54] METALLIZING CHAMBER VIEWING SYSTEM 3 Chins 2Drawing ABSTRACT: A mirror is placed within a metallizing chamber [52]U.S. Cl 350/301, h in a transparent viewing port in a position so as toshield 1 the viewing port from the metal source. The mirror is also [51]Int. Cl. G02]! 5/08 positioned to reflect a view of the object beingmetallized [50] Field of Search 350/288, thr ugh th viewing en Ifrequired,-a second mirror may be 299, 30L 3l9; l 18/9, 8. 48-495 used toreflect a view of the object to the first mirror.

PATENTEU NOV 1 6 I97! SHEET 2 [IF 2 POWER SUPPLY fl ff mm a Z m WE w134% 0 w 3 METALLIZING CHAMBER VIEWING SYSTEM BACKGROUND CONTRACTUALORIGIN OF THE INVENTION The invention described herein was made in thecourse of, or under, a contract with the UNITED STATES ATOMIC ENERGYCOMMISSION.

BACKGROUND OF THE INVENTION A.process commonly used for metallizing anobject involves the vacuum evaporation of the metal used. The vacuumevaporation is normally carried out in a glass bell jar or similarenclosure which is evacuated for the purpose. It is sometimes necessaryto make a visual examination of the object which is being metallizedduring the metallizing process. However, the metal being evaporatedquickly coats the inside surface of the jar, obscuring the object beingviewed. Many devices have been developed for keeping at least a portionof the jar clean, but these devices are complex and of limited use. Inmost of these devices the transparent area is quickly covered with themetal, so that a new transparent area must be uncovered.

Eventually there is no remaining transparent area available for viewing.

It is therefore an object of this invention to provide an improveddevice for observing an object in an enclosure during a metallizingprocess.

Another object of this invention is to provide a device having anobserving window which remains transparent during the metallization ofan object.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS The inventionis shown in the drawings of which:

FIG. 1 is a cross-sectional view of a metallizing system using a singlemirror; and

FIG. 2 is a cross-sectional view of a metallizing system using a pair ofmirrors.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, an objectwhich is to be metallized is positioned on a stand 11 within themetallizing chamber. A bell jar l3 and a base 12 form an enclosure whichcan be sealed and in which a vacuum can be maintained in a wellknownmanner. A filament 16 which contains the metal to be evaporated isconnected to a power supply 17 through wire 14. Wire 14 enters theenclosure through a sealed opening 15 in the base 12 of the metallizingsystem.

In normal operation, the metal which is evaporated from filament 16travels in straight lines 19. The evaporated metal travels equally wellin all directions and therefore coats the sides of bell jar 13 as wellas object 10. The evaporated metal forms a thin coating 20 around theinside of the bell The coating 20 quickly becomes opaque, blocking theview of object 10 within the metallizing system. I

In order to provide a means for viewing the object during the entiremetallizing operation, a mirror 22 is positioned within the bell jar 13so as to block the metal evaporated from filament 16. This provides aclear viewing port 23 in bell jar 13. The mirror 22 is positioned at anangle so as to reflect the image of the object through the viewing port23 so that it can be seen by an observer.

Refemng to FIG. 2, there is shown a second embodiment of the inventionin which two mirrors are sued. Identical parts of the metallizing systemhave the same reference numerals. Mirror 25 is positioned within thebell jar 13 so as to block the metal evaporated from filament 16. Thisprovides a clear viewing port 27 in bell jar 13. A second mirror 26 ispositioned to reflect the image of the object into mirror 25. The anglesof mirrors 25 and 26 are adjusted so that the image of the object isreflected out of viewing port 27 so that it can be seen by an observer.

The structure of FIG. 2 is useful only with a metal which is capable ofreflecting sufficient light to produce an image of the object outside ofthe bell jar. The metal from filament 16 will be deposited on thesurface of mirror 26, coating the mirror. With a reflective material theimage quality is not degraded, since the reflected coating on mirror 26is constantly renewed. This system is very useful with metals such asaluminum and silver, however, it is not limited to these metals but anyreflective material may be used With the structure of FIG. 1, however,the reflective surface of mirror 22 is not exposed. to the vaporizedmetal. Thus with this structure the material vaporized need not bereflective.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A viewer for vacuum-metallizing equipment for depositing a metal filmon an object, comprising: a cover having a single sealed opening mountedon a base plate such that the base plate seals said opening, said coverhaving an evenly contoured exterior surface and further having atransparent area which serves as a viewing port therein; a vacuumchamber defined between said base plate and the interior surface of saidcover; means communicating with said vacuum chamber through said baseplate for evacuating said chamber to create a vacuum therein; meansassociated with said base plate for supporting the object within saidvacuum chamber; a metal evaporation source mounted on said base platewithin said vacuum chamber; a first mirror positioned within said vacuumchamber between said evaporation source and said viewing port to shieldsaid viewing port from evaporated metal from said evaporation source,said first mirror having a reflective surface visible from said viewingport, said first mirror further being positioned to reflect an image ofthe object through said viewing port.

2. The viewer of claim 1 wherein, the metal film deposited on the objectis reflective.

3. The viewer of claim 2 further including, a second mirror having areflective surface and positioned within said cover for reflecting animage of the object to said first mirror and through said viewing port.

1. A viewer for vacuum-metallizing equipment for depositing a metal filmon an object, comprising: a cover having a single sealed opening mountedon a base plate such that the base plate seals said opening, said coverhaving an evenly contoured exterior surface and further having atransparent area which serves as a viewing port therein; a vacuumchamber defined between said base plate and the interior surface of saidcover; means communicating with said vacuum chamber through said baseplate for evacuating said chamber to create a vacuum therein; meansassociated with said base plate for supporting the object within saidvacuum chamber; a metal evaporation source mounted on said base platewithin said vacuum chamber; a first mirror positioned within said vacuumchamber between said evaporation source and said viewing port to shieldsaid viewing port from evaporated metal from said evaporation source,said first mirror having a reflective surface visible from said viewingport, said first mirror further being positioned to reflect an image ofthe object through said viewing port.
 2. The viewer of claim 4 wherein,the metal film deposited on the object is reflective.
 3. The viewer ofclaim 2 further including, a second mirror having a reflective surfaceand positioned within said cover for reflecting an image of the objectto said first mirror and through said viewing port.